Britain is seeking to win support at the United Nations for a no-fly zone in Libya, amid fears that any military action to prevent Muammar Gaddafi's assault on opposition forces may come too late.

The UN Security Council was meeting in New York to consider a resolution tabled by Lebanon, with UK and French backing, which presents a series of options for increasing pressure on the Gaddafi regime, including tougher sanctions and a no-fly zone.

Prime Minister David Cameron acknowledged that there was "a wide range of views" on the Security Council about how best to deal with the Libyan dictator. But he insisted that action must be taken to "get rid of this regime", and urged the UN to "show some leadership".

French President Nicolas Sarkozy also appealed to the Security Council to back the resolution in a letter addressed to the heads of the 15-member body.

The urgency of deliberations at the UN was heightened by growing signs that Gaddafi's forces are gaining the upper hand over the opposition groups who have staged a month-long rebellion against his 42-year rule.

The Libyan leader's son Saif said that Government forces were closing in on rebel stronghold Benghazi and confidently predicted that the revolt would be over within 48 hours.

Saif Gaddafi told ITN: "Wait and see the next two days what will happen in the east of Libya. You will see the millions there happy for their liberation from the dark forces - you will see."

Gaddafi claimed that the leaders of the uprising were already fleeing to Egypt, and promised that no revenge would be taken on captured rebels, many of whom he claimed were teenagers of 13 or 14 who had been forced to fight.

UN Secretary General Ban Ki-Moon called for an "immediate ceasefire" by all sides, warning that a bombardment of Benghazi would "massively place civilian lives at risk".

US Secretary of State Hillary Clinton said she hoped the Security Council would take a vote on the resolution "no later than Thursday", but made clear that this might involve approval of measures short of a no-fly zone.